As the application of Internet techniques has spread, so too has the provision and availability of information distribution services. According to common information distribution services, not only registrations of information for specifying users, such as the e-mail addresses of distribution destinations and the names or the categories of users, but also registrations covering desired information fields and distribution times are accepted. A distribution service provider selects information in accordance with registered preferences and distributes the information to users.
Ordinary users do not always desire to receive all the information that is available from a distribution service provider. Therefore, the general rule is for users to set conditions, such as desired fields, for the distribution of information, and that they receive only that information which matches the conditions they have established. If users do not make such selections, under present conditions an enormous amount of information will cross over to the user. This will not only contribute to an increase in communication traffic, but also, data that users truly require will be scattered through and hidden in a huge amount of irrelevant, unwanted information, and the effective distribution of information will be disrupted.
Thus, means for filtering the variety of information that is available for distribution has been proposed. For example, in Japanese Unexamined Publication No. Hei 11-51666 or No. 9-281918, means is disclosed for searching for information appropriate to the current location of a user, while referring to the current location information for a terminal though which an information distribution request was issued, and for distributing the information. Further, in Japanese Unexamined Publication No. Hei 11-252003, a method is disclosed for providing a personal information search service or an additional information service by referring to a history of visits made to a service area. In addition, in Japanese Unexamined Publication No. Hei 11-355854, a method is disclosed for permitting the collection of information desired by a terminal from among service data distributed by a base station.
In order to use the above methods to filter the information to be distributed, certain personal information is naturally required. Since a distribution server is in charge of filtering the information to be distributed, the personal information must be held by the server. That is, either intentionally or unintentionally, personal information must be disclosed to a distribution source in order for it to select, from among available data, that data in which a specific user should be interested, i.e., information that the user will find useful. When, for example, property information is to be distributed to a user who plans to purchase real estate, valid and relevant information can be distributed only so long as the annual income (purchasing capability) of the user is readily available. Further, when a person having a clinical treatment history desires to obtain information concerning a diet, the clinical history may be inferred by referring to the selected information. Further, to distribute detailed information in real time with very little delay, even without referring to the previous examples, it is evident that an even greater amount of detailed personal information will be required.
However, originally, personal information should be handled with care. Further, it is a given that personal information must not be disclosed without the permission of the users. It is also believed that many users abandon the idea of registering their personal data with a distribution source because they hesitate to disclose it. In addition, users are always apprehensive about the security that their personal information will be afforded, and that adequate measures will be taken to keep it secret. Therefore, this situation may be a factor in preventing the more effective use of information distribution systems.
As another application method, a server does not hold any personal information, or holds only minimum required personal information, and distributes it without performing any special screening of the material. However, when this method is employed, a greater load is imposed on a network and on computers used for information distribution due to an increase in communication traffic. In addition, information that has been requested and is truly required, may be mixed in with a large amount of other, extraneous information, which may prevent its ready distribution.
It is, therefore, one objective of this invention to provide means for distributing only truly necessary information, selected from among the huge amount of information that is available, while providing adequate security for personal information that must be kept secret. It is another objective of this invention to provide means for appropriately selecting necessary information, without increasing communication traffic and without disclosing personal information.